Divestitures Divestitures - Schedule of assets and liabilities held for sale (Details) - FGL [Member] - USD ($) $ in Millions	Dec. 31, 2016	Sep. 30, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Investment	$ 21,192.8	$ 21,140.9
Disposal Group, Including Discontinued Operation, Cash and Cash Equivalents	631.9	863.9
Disposal Group, Including Discontinued Operation, Accrued Investment Income	200.7	213.7
Disposal Group, Including Discontinued Operation, Reinsurance Recoverable	3,443.7	3,463.9
Disposal Group, Including Discontinued Operation, Deferred Tax Assets	47.2	0.0
Disposal Group, Including Discontinued Operation, Property, Plant and Equipment	19.7	18.5
Disposal Group, Including Discontinued Operation, Intangible Assets	1,270.9	1,065.5
Disposal Group, Including Discontinued Operation, Other Assets	213.0	335.1
Disposal Group, Including Discontinued Operation, Write-down of assets held for sale to fair value less costs to sell	(218.3)	(362.8)
Disposal Group, Including Discontinued Operation, Assets [Abstract]
Disposal Group, Including Discontinued Operation, Assets	26,801.6	26,738.7
Disposal Group, Including Discontinued Operation, Insurance Reserves	24,134.3	23,944.6
Disposal Group, Including Discontinued Operation, Debt	400.0	398.8
Disposal Group, Including Discontinued Operation, Accounts Payable and Accrued Liabilities	39.6	57.0
Disposal Group, Including Discontinued Operation, Deferred Tax Liabilities, Current	0.0	9.9
Disposal Group, Including Discontinued Operation, Other Liabilities	626.6	689.9
Disposal Group, Including Discontinued Operation, Liabilities	$ 25,200.5	$ 25,100.2